It is known to provide a pipette configured to grasp a pipette tip to transfer a quantity of liquid with the pipette tip. Once the quantity of liquid is transferred, the conventional pipette is known to include an ejector to eject the pipette tip from the pipette. It is important to provide an ejector that is appropriately fitted to accommodate the particular size and design of the desired pipette and/or pipette tip. If inappropriately sized, a new ejector must be located and fitted to accommodate the particular combination of features presented by the pipette and/or pipette tip. As such, there is a need to provide ejectors that may be quickly adjusted to the appropriate size, easily removed for possible servicing or replacement with another appropriate ejector design, and lock the adjusted position of the ejector member to prevent inadvertent change of an optimum adjusted position.
U.S. Pat. No. 7,264,779 to Viot, hereinafter Viot, discloses a known pipette. As shown in FIG. 1 of Viot, the pipette includes a control button 12, an actuator 14, a connection screw 16 and a knurled wheel 18. The pipette of Viot further includes an ejector rod 20 for separating a cone that is fixed to the pipette. As shown in FIG. 11 of Viot, at its top end, the ejector rod 20 presents a top vertical duct 52 extending to a notch 56 extending horizontally. The knurled wheel 18 can be received in the notch 56 and includes a central threaded bore for forming a screw-and-nut connection with the shank 46 of a screw 16. The screw 16 also has a male coupling portion 38 that may be received in a female coupling portion 22 of the actuator. Col. 5, lines 9-12 discloses a bayonet connection may be used to connect the ejector rod 20 to the actuator 14. Viot, however, fails to disclose a lock device for inhibiting adjustment of the extended position of the ejector rod. As such, the design of Viot promotes inadvertent adjustment of the ejector rod 20 after a desired adjustment is achieved.
U.S. Pat. No. 6,833,114 to Christen et al., hereinafter Christen et al., discloses another pipette with an ejector device 6 including an ejector mechanism 16, 16′ which can be displaced to eject a tip 8 from the pipette. The ejector device 6 includes a device for adjusting position 24, 24′, 33, 33′, 39, 39′ which is arranged in such a way that it is possible to modify the limit position reached by an ejection end 22, 22′ of the ejector device at the end of a stroke. The device for adjusting position 24, 24′ involves discrete adjustment positioning of the ejection end to discrete positions without the ability to maintain an adjusted position between the predetermined discrete positions defined by the engagement between the notches 31′ and the bump 32″ illustrated in FIG. 5. The devices for adjusting position 39, 39′ illustrated in FIGS. 7 and 8 likewise involve discrete adjustment positioning of the ejection end in discrete positions. FIGS. 6 and 9 disclose devices 33, 33′ including a thread 35, 35′. However, like Viot, Christen et al. fails to disclose a lock device for inhibiting adjustment of the extended position of the ejector rod. As such, Christen et al. likewise promotes inadvertent adjustment of the ejector rod 20 after a desired adjustment is achieved.
From Polish patent application No. P-381 071 and from international patent application No. PCT/PL2007/000077 is known an exchangeable tip ejection device in a pipette built of a handle 1 and a nozzle 2 and of, coupled with them, a pipetting push-button and a drawing up and discharging mechanism. Said ejection device comprises an ejector push-button 3 seated in the upper part of the pipette handle 1, an ejector 4 by its lower end seated onto the pipette nozzle 2 and an assembly for continuous adjustment of the ejector length, which assembly for continuous adjustment of the ejector length is arranged between the ejector push-button 3 and the ejector 4. The assembly for continuous adjustment of the ejector length is the connection of a “turnbuckle” type. The ejector 4 comprises an ejector rod 6 and an ejector arm 9, whereas the ejector rod 6 is coupled with the ejector push-button 3, the ejector arm 9 is seated by its lower end onto the pipette nozzle 2, and the ejector rod 6 and the ejector arm 9 are coupled with each other with formation the cylindrical joint of the axis of rotation perpendicular to the longitudinal axis X of the pipette nozzle 2.
As such, there is a need to provide an infinitely adjustable ejection end that can be locked in a desired position. There is also a need to incorporate the lock into an actuator member to reduce parts and simplify the lock design.
There is also a need to provide an ejection mechanism that may provide audible and/or vibrational feedback to indicate when a connected position is achieved between the ejection mechanism and the body of the pipette.
There is also a need to provide at least one stop to limit adjustment of the extended position of the ejector end with respect to the body.